The invention relates to electromagnetic shielding, and in particular to an electromagnetic shielding laminate and a method of producing such a laminate.
Electromagnetic shielding laminates comprising two panes of glass, a plastics interlayer between the panes and an electroconductive wire mesh embedded in the interlayer are known. In order to provide electromagnetic shielding, the whole area of the laminate must be electrically conductive, and the electroconductive element must be connected to earth around the whole periphery of the laminate. This is achieved by using a wire mesh which extends over the whole area of the laminate and beyond the edges of the laminate around the whole periphery of the laminate to make electrical contact with an electroconductive frame in which the laminate is mounted.
Another known form of electromagnetic shielding laminate comprises two panes of glass with a plastics film carrying an electroconductive coating between the panes. The coated plastics film extends beyond the periphery to make electrical contact, for example with a surrounding metal frame.
There are advantages to be gained by using glass carrying an electroconductive coating directly on the glass surface for electromagnetic shielding. However, when the coated glass is to be laminated with the coating inwards, a problem arises in making electrical contact with the electroconductive coating around the periphery of the laminate. The problem is more difficult to solve when the electroconductive coating comprises a non-conductive layer over an electroconducting layer, as for example in commercially available low emissivity coated glasses such as Pilkington's KAPPAFLOAT glass.
It has now been found that the problem can be overcome by including a border of fine conductive mesh in the laminate between a plastics interlayer and a pane carrying the electroconductive coating.